The Premisses, Not to Be Contended
- the 2nd version Elmarit is, without the slightest doubt, technically
superior
- the Elmarit is also faster with a maximum aperture of f/2.8 vs. the f/4.5
of the Cooke
- the uncoated Cooke has lower contrast and higher attenuation than the MC
Elmarit
- the original 4.25" x 3.25" camera didn't even ask for pixel peeping
level sharpness
- my Cooke is slightly damaged, which affects the IQ at the maximum
aperture of f/4.5
so it must be used at f/5.6 or slower if IQ and especially contrast is important
- my Cooke may also be rather poorly aligned due to a plethora of reasons,
like rough handling during the years and the mounting method I've employed
- consequently, a rigorous test is both unnecessary and not even very
meaningful
Mitigating Factors
- I don't very often shoot at faster than f/4 or even f/5.6
- in digital photography, quite a lot can be done during processing,
much more easily and faster than in the wet darkroom
- shooting RAW and working at 16 bits (or more), the quality degradation
caused by reasonable adjustments is often quite minimal and unnoticeable, of no
consequence
- in real photography, ultimate technical quality is very rarely
the decisive ingredient
The Question, the Real Question
Can a 90 years old, slightly battered lens deliver
a worthwhile IQ, now?
- The Elmarit is there just to afford a reference point for the
Cooke photos
Getting at it
- The first thing to note is that images of the size usually used on the Web
really tell very little about the quality of lenses, even a few 100% crops aren't sufficient
for this purpose
- Given all the uncertainties of focusing, irrespective whether MF or AF,
full-size images ought to be examined when sufficiently large, high quality prints are not
available.
- all shots were taken at f/5.6, using both lenses with a lens hood
- NB. here the down-sampled photos have not been sharpened for screen display
- NB. the vignetting in the Cooke photos is caused by the Edixa bayonet of
the bellows
- NB. it was late afternoon, which affects both contrast and WB
- NB. there was a thin mist all over the place due to warm, moist air
flowing in
from the South. However, the effect seems to have been mostly minor.
- the Cooke was perhaps more affected by the mist as it seems significantly
cooler
than the Elmarit, almost as if the photos were taken at noon
- single shots only with each lens, all the eight comparison shots were
taken within less
than five minutes, first a series of four shots with the Elmarit, then with
the Cooke
- I tried to focus identically, but didn't always quite succeed,
but that's just life
- the Elmarit was difficult to focus with due to the very small adjustments
required for pixel peeping accuracy when focusing at distances of about 100-200 m
- the Cooke was easier to focus with due to the more sensitive
bellows focusing, but still the results weren't always quite perfect
- despite the problems, any reasonably sized print would probably be
sharp enough
- identical exposure with both lenses trying to avoid even the
slightest over-exposure, the Elmarit used as a reference knowing it to have less attenuation
- there is a discernible exposure difference as the Cooke is uncoated,
and I have therefore included two versions of the full-size Cooke photos,
both without and with a 0.20 stop compensation plus some BP adjustment to compensate for
the lower contrast of the Cooke
- here, the Elmarit exhibits only very minor purple fringing and CA, but
the Cooke practically none at all, in fact, it almost seems to behave like a good APO
- the focal length of the Cooke seems to be more like 5.6" (143 mm) than the
nominal 5.5", there is an easily discernible magnification difference between the lenses
- the RAW photos were processed with LightZone, always the Elmarit shot of a
pair first, then the corresponding Cooke shot using exactly the same settings
- the full-size images have been minimally sharpened to compensate for
the 5D AA filter
- also the sharpened versions are sharpened only rather lightly,
trying to avoid halos
- there are crops of the Cooke photos only as it is the main subject of this
exercise
|
|
Finally, the Photos
Note: All shots hand-held
Elmarit
|
Cooke
|
9392 Elmarit (
Full-size )(
Sharpened )
Slightly back-focused, sharp to infinity
9399 Cooke (
Full-size )(
Sharpened )(
Full-size, sharpened, +0.2
)
Slightly front-focused, softness starts almost immediately after the bow
of the boat,
that is, softness visible at 100% only.
9399 Cooke, crop, sharpened, exp +0.2
Elmarit
|
Cooke
|
9393 Elmarit (
Full-size )(
Sharpened )
Slightly front-focused, background buildings soft
9398 Cooke (
Full-size )(
Sharpened )(
Full-size, sharpened, +0.2
)
Back-focused, background buildings very sharp compared to the buildings at
the waterfront
9398 Cooke, crop, sharpened, exp +0.2
Elmarit
|
Cooke
|
9394 Elmarit (
Full-size )(
Sharpened )
9397 Cooke (
Full-size )(
Sharpened )(
Full-size, sharpened, +0.2
)
Elmarit
|
Cooke
|
9395 Elmarit (
Full-size )(
Sharpened )
9396 Cooke (
Full-size )(
Sharpened )(
Full-size, sharpened, +0.25
)
9396 Cooke, crop, sharpened, exp +0.25
|
A couple of shots with the Cooke only, a Few Minutes Later
9401 Cooke (
Full-size )(
Sharpened )
9401 Cooke, crop, sharpened
9402 Cooke (
Full-size )(
Sharpened )
9402 Cooke, crop, sharpened
|
Quite a respectable performance by a 90 years old LF lens!
- the Cooke certainly has enough sharpness and resolution for most real
life purposes
- comparing the photos taken with this lens to the photos taken with
my other lenses longer than 100 mm, the Cooke seems to exhibit the least amount of CA and
quite a negligible amount of purple fringing - even compared to the 4/180 APO-Lanthar
- of course, the contrast is lower than that of a modern MC lens, and
there is a little bit more lens flare, but most often some post-processing can do a lot to
mitigate
- besides, my contraption is a semi-macro, focusing down to about 1:1.6
- after all this testing, I consider the Cooke one of my most usable lenses,
probably fated to be my favourite lens at around 135 mm, superceding the Elmarit-R,
partly for philosophical reasons, for the deep sense of satisfaction
derived from the employment of a relatively ancient lens for high quality digital photography
|
Taylor, Taylor & Hobson
Series II Cooke Anastigmat 5 1/2 inch f/4.5 for 4 1/4 x 3 1/4 in.
For adapting and mounting the thing on a dSLR, see e.g.
this page.
|
